Field of the Invention
The present invention relates to a liquid ejection head for ejecting a liquid, e.g., ink, and a method for manufacturing the same.
Description of the Related Art
Recording of characters, images, and the like and a surface treatment by a liquid ejection head typified by an inkjet recording head are performed by imparting thermal energy or vibration energy to a liquid, e.g., ink, and ejecting the liquid as very small droplets from an ejection port so as to apply the liquid to a predetermined position on a recording medium. Japanese Patent Laid-Open No. 2002-019120 describes a method for manufacturing a liquid jet recording head which is one form of the liquid ejection head.
In the manufacturing method disclosed in Japanese Patent Laid-Open No. 2002-019120, a recording element substrate having an ejection port, a flow passage, an ejection energy generation element, and the like is attached to a supporting plate composed of alumina or the like, and the recording element substrate is electrically bonded to a flexible printed circuit board serving as an electric wiring member.
Subsequently, a peripheral sealant for protecting the side surface of the recording element substrate from ink, dust, and the like is applied. After the peripheral sealant is cured, an inner lead bonding (ILB) sealant (electrical connection portion sealant) for sealing an electrical connection portion is applied thereto.
The functions required of the peripheral sealant used for sealing the peripheral portion of the recording element substrate and the electrical connection portion sealant are as described below.
The peripheral sealant is required to flow into a gap with a width of less than 1 mm, which is formed between a part on the supporting plate and the recording element substrate, in a short time so as to fill the gap promptly. In addition, it is necessary to protect the recording element substrate from ink and other factors.
The electrical connection portion sealant is required to seal the electrical connection portion, as a matter of course. In addition, it is required that the sealant does not peel when rubbed with a blade, a wiper, or the like for cleaning a surface provided with an ink ejection port or when coming into contact with paper and the like because of paper-jamming.
Japanese Patent Laid-Open No. 2005-132102 describes a method in which a peripheral sealant and an electrical connection portion sealant are cured at the same time so as to improve the production efficiency. Japanese Patent Laid-Open No. 2005-132102 describes a method in which the hardness of the electrical connection portion sealant after curing is made higher than the hardness of the peripheral sealant after curing, the electrical connection portion sealant and the peripheral sealant are made to contain the same material as the base agent and the curing agent, and these sealants are stacked by coating.
According to this method, even when the peripheral sealant and the electrical connection portion sealant are cured at the same time, a difference in reactivity with a curing agent between the two sealants due to a difference in the curing rate between the two sealants (hindrance to curing) does not occur.